1. Field of the Invention
The present invention concerns a method of making a judgment on emotional positivist or negativity by detecting asymmetry of brain waves of left and right cerebral hemispheres, and a storage medium for storing a computer program to execute such method.
2. Technical Background
Electroencephalography is a technique for recording and interpreting the electrical activity of the brain. The nerve cells of the brain generate electrical signals that fluctuate rhythmically in distinct patterns. These brain-wave patterns are measured and recorded by an instrument called an electroencephalograph, and the recording produced by such an instrument is called an electroencephalogram, commonly abbreviated EEG. To measure the EEG, electrodes are placed on the scalp. Each electrode transmits a signal to one of several recording channels of the electroencephalograph. This signal consists of the difference in the voltage between the electrode and a reference electrode. Electroencephalograph provides a means of studying how the brain works and of tracing correlation between one part of the central nervous system and another. Besides, biofeedback training with brain waves has also been useful in enhancing mental functioning. xe2x80x9cAlpha (wave) trainingxe2x80x9d elicits the calming and integrative effects of meditation. Theta wave training has led to more focused attention, the control of xe2x80x9cmental blocksxe2x80x9d during examinations, and the control of anxiety.
Recently, there has been developed a human-computer interface (hereinafter simply referred to as xe2x80x9cinterfacexe2x80x9d) that employs brain waves to operate a computer without operating keyboard. Such conventional interface requires the user to be trained to generate particular kinds of brain waves such as alpha wave or asymmetrical waves between the left and right cerebral hemispheres. In order to make a judgment on the psychological state of the user, the data of the brain waves are fully detected throughout the reaction time, for example 10 to 30 seconds, so that the interface is too slow to effectively operate the computer. In addition, a plurality of electrodes must be attached to the scalp, thus making the user inconvenient.
It is an object of the present invention to provide a method of making a judgment on emotional positivist or negativity of a person without any preparatory training of the person, and a storage medium for storing a program for executing such method.
According to an aspect of the present invention, a method of making a judgment on emotional positivist or negativity of a person comprises the steps of obtaining asymmetry ratio between the brain waves of the left and right cerebral hemispheres measured in a given unit time by means of electrodes attached to the left and right side of the scalp, calculating asymmetry ratio versus time at each frequency of the measured brain waves if the time taken for measuring the brain waves exceeds a given time interval, calculating a change rate of the asymmetry ratio of the previous step with time, and entering the change rate into an artificial neural network to make a judgment on the emotional positivity or negativity.
According to another aspect of the present invention, there is provided a computer storage medium for storing a computer program executed by a computer, wherein the computer program is composed of performing the functions of obtaining asymmetry ratio between the brain waves of the left and right cerebral hemisphere measured in a given unit time by means of electrodes attached to the left and right side of the scalp, calculating asymmetry ratio versus time at each frequency of the measured brain waves if the time taken for measuring the brain waves exceeds a given time interval, calculating a change rate of the asymmetry ratio of the previous step with time, and entering the change rate into an artificial neural network to make a judgment on the emotional positivity or negativity.